METHOD FOR PRODUCING 2-CHLORO-3,3,3,-TRIFLUOROPROPENE (HCFC-1233xf)

ABSTRACT

The present invention relates to an improved method for manufacturing  2 -chloro- 3,3,3, -trifluoropropene (HCFC- 1233 xf) by reacting  1,1,2,3 -tetrachloropropene,  1,1,1,2,3 -pentachloropropane, and/or  2,3,3,3 -tetrachloropropene with hydrogen fluoride, in a vapor phase reaction vessel in the presence of a vapor phase fluorination catalyst and stabilizer. HCFC- 1233 xf is an intermediate in the production of  2,3,3,3 -tetrafluoropropene (HFO- 1234 yf) which is a refrigerant with low global warming potential.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuing application of U.S. application Ser.No. 12/179,055, filed Jul. 24, 2008, which claims the priority benefitof U.S. Provisional Application No. 60/951,796, filed Jul. 25, 2007,which are incorporated herein by reference.

BACKGROUND

1. Field of the Invention

The present invention relates to a method for manufacturinghydrochlorofluoroolefins. More particularly, this invention relates tosynthesis of 2-chloro-3,3,3,-trifluoropropene (HCFC-1233xf).

2. Description of Related Art

Fluorocarbon based fluids have found widespread use in industry in anumber of applications, including as refrigerants, aerosol propellants,blowing agents, heat transfer media, and gaseous dielectrics. Because ofthe suspected environmental problems associated with the use of some ofthese fluids, including the relatively high global warming potentialsassociated therewith, it is desirable to use fluids having the lowestpossible greenhouse warming potential in addition to zero ozonedepletion potential. Thus there is considerable interest in developingenvironmentally friendlier materials for the applications mentionedabove.

Tetrafluoropropenes, having essentially zero ozone depletion and lowglobal warming potential, have been identified as potentially fillingthis need. However, the toxicity, boiling point, and other physicalproperties in this class of chemicals vary greatly, even betweendifferent isomers of a compound. One tetrafluoropropene having valuableproperties is 2,3,3,3-tetrafluoropropene (HFO-1234yf). HFO-1234yf hasbeen found to be an effective refrigerant, heat transfer medium,propellant, foaming agent, blowing agent, gaseous dielectric, sterilantcarrier, polymerization medium, particulate removal fluid, carrierfluid, buffing abrasive agent, displacement drying agent and power cycleworking fluid. Thus, there is a need for new manufacturing processes forthe production of tetrafluoropropenes and in particular2,3,3,3-tetrafluoropropene.

One process for producing tetrafluoropropenes involves the use oftetrachloropropenes as a reactant (U.S. 2007-0197842 A1). Additionally,several other methods of preparing hydrofluoroalkenes are known. Forexample, U.S. Pat. No. 4,900,874 (Ihara et al) describes a method ofmaking fluorine containing olefins by contacting hydrogen gas withfluorinated alcohols. U.S. Pat. No. 2,931,840 (Marquis) describes amethod of making fluorine containing olefins by pyrolysis of methylchloride and tetrafluoroethylene or chlorodifluoromethane. Thepreparation of HFO-1234yf from trifluoroacetylacetone and sulfurtetrafluoride has been described. See Banks, et al., Journal of FluorineChemistry, Vol. 82, Iss. 2, p. 171-174 (1997). Also, U.S. Pat. No.5,162,594 (Krespan) discloses a process wherein tetrafluoroethylene isreacted with another fluorinated ethylene in the liquid phase to producea polyfluoroolefin product.

Notwithstanding prior teachings, applicants have come to appreciate acontinuing need for methods of efficiently preparing intermediates ofcertain hydrohalocarbons, particularly compounds which are in partuseful as intermediates in the preparation of tetrafluoropropenes, suchas 2,3,3,3-tetrafluoropropene (HFO-1234yf).

The prior art discloses various processes for the preparation ofpolyhaloolefin products that involve separate steps as well as disparatereaction conditions, reagents, and catalysts. The efficiency of suchmulti-step processes is thus limited by the efficiency of eachindividual step. As such, one inefficient step may make the entireprocess more resource intensive, less effective at convertingintermediates to the desired fluorocarbon products and less productive,suffering yield losses due to increased impurity formation.

The present invention offers a less resource-intensive process thatproduces increased conversion of intermediates to the end productpolyhaloolefin over a longer period due to substantially increasedcatalyst life. This is achieved by Applicants' discovery of subjecting atetrachloropropene to fluorination with a fluorinating agent and acatalyst in the presence of a stabilizer.

SUMMARY OF THE INVENTION

Applicants have discovered an improved method for producing atetrahalopropene, such as 2-chloro-3,3,3,-trifluoropropene, thatinvolves reacting one chlorocarbon or mixed chlorocarbon feed materialselected from the group of 1,1,2,3-tetrachloropropene,1,1,1,2,3-pentachloropropane (HCC-240db), and 2,3,3,3-tetrachloropropenewith hydrogen fluoride, in a vapor phase reaction vessel and in thepresence of a vapor phase fluorination catalyst and at least onestabilizer, and at conditions effective to produce the desiredtetrahalopropene.

Preferably, the preferred contacting step produces a reaction productcomprising tetrahalopropene, and in particular2-chloro-3,3,3-trifluoropropene (HFO-1233xf). In preferred embodiments,the contacting step comprises reacting a tetrachloropropene and/orpentachloropropane with a fluorinating agent, such as HF, in the gasphase in the presence of at least one catalyst and at least onestabilizer. In a particularly preferred embodiment, the catalyst isCr₂O₃ and the stabilizer is di-isopropyl amine. In certain preferredembodiments, the conversion of the tetrachloropropene is from about 70%to about 100% and the selectivity for HFO-1233xf is from about 50% toabout 99%.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

One beneficial aspect of the present invention is that it enables theproduction of desirable haloolefins, preferably C3 haloolefins, withoutthe inefficiency of short-lived catalyst underperformance. Morespecifically, certain preferred embodiments of the present inventioninvolve producing the desired C3 haloolefins using the combination of atleast one catalyst and at least one stabilizer. Applicants havediscovered that the use of at least one stabilizer in conjunction withthe catalyst component results in a significant improvement in catalystlongevity. In a preferred embodiment, catalyst longevity is improved byat least 43%, and more preferably by at least 50%. The resulting processis significantly more efficient and cost-effective as it thus usesreduced catalyst amounts and results in greater conversion of startingmaterials to the desired product.

Applicants have recognized that the production of one or more of thedesired haloolefins, in particular hydrofluoropropenes, was inefficientdue to unusually poor catalyst performance. By way of non-limitingexplanation, as further detailed below, such poor performance may be theresult of a side polymerization reaction or coking involving thecatalyst. Applicants have also unexpectedly discovered that the presenceof a stabilizer in the reaction mixture substantially prevents thispolymerization or coking and, in a preferred embodiment, improvescatalyst performance, preferably by at least 43%, more preferably by atleast 50%, than that of reactions conducted with catalyst in the absenceof stabilizer.

Preferably, 1,1,2,3-tetrachloropropene, 2,3,3,3-tetrachloropropene, or1,1,1,2,3-pentachloropropane or mixture thereof is exposed to reactionconditions to produce a reaction product comprising2-chloro-3,3,3,-trifluoropropene. Preferred embodiments of the preferredprocess are described below in non-limiting detail.

The methods of the present invention preferably comprise reacting onechlorocarbon or mixed chlorocarbon feed material selected from the groupof 1,1,2,3-tetrachloropropene, 1,1,1,2,3-pentachloropropane (HCC-240db),and 2,3,3,3-tetrachloropropene with a fluorinating agent to produce afluorinated haloolefin, preferably a C3 fluorinated haloolefin, morepreferably 2-chloro-3,3,3,trifluoropropene (HFC-1233xf). This preferredreaction step may be described, by way of illustration but notnecessarily by way of limitation, by the following reaction equation inconnection with embodiments in which the tetrachloropropene is1,1,2,3-tetrachloropropene and the fluorinating agent is hydrogenfluoride:

CH₂ClCCl=CCl₂+3HF→CF₃CCl=CH₂+3HCl.

In certain preferred embodiments, the present converting step is carriedout under conditions effective to provide a tetrachloropropeneconversion of at least about 40%, more preferably at least about 55%,and even more preferably at least about 70%. In certain preferredembodiments the conversion is at least about 90%, and more preferablyabout 100%. Further in certain preferred embodiments, the conversion ofthe tetrachloroproene to produce a C3 haloolefin is conducted underconditions effective to provide a C3 haloolefin selectivity of at leastabout 85%, more preferably at least about 90%, and more preferably atleast about 95%, and even more preferably about 100%.

In a particularly preferred embodiment, the invention relates to acontinuous method for producing 2-chloro-3,3,3,-trifluoropropene(HCFC-1233xf) by vapor phase fluorination of one chlorocarbon or mixedchlorocarbon feed material selected from the group of1,1,1,2,3-pentachloropropane (HCC-240db), 2,3,3,3-tetrachloropropene,and 1,1,2,3,-tetrachloropropene (HCC-1230xf) with hydrogen fluoride toproduce a stream comprising hydrogen fluoride,2-chloro-3,3,3,-trifluoropropene and hydrogen chloride.

This reaction may be conducted in any reactor suitable for a vapor orliquid phase fluorination reaction. Preferably the reactor isconstructed from materials which are resistant to the corrosive effectsof hydrogen fluoride and catalyst such as Hastalloy, Inconel, Monel andvessels lined with fluoropolymers. In case of a vapor phase process, thereactor is filled with a vapor phase fluorination catalyst. Anyfluorination catalysts known in the art may be used in this process.Suitable catalysts include, but are not limited to chromium, aluminum,cobalt, manganese, nickel and iron oxides, hydroxides, halides,oxyhalides, inorganic salts thereof and their mixtures. Combinations ofcatalysts suitable for the present invention nonexclusively includeCr₂O₃, FeCl₃/C, Cr₂O₃/Al₂O₃, Cr₂O₃/AlF₃, Cr₂O₃/carbon,CoCl₂/Cr₂O₃/Al₂O₃, NiCl₂/Cr₂O₃/Al₂O₃, CoCl₂/AlF₃, NiCl₂/AlF₃ andmixtures thereof. Chromium oxide/aluminum oxide catalysts are describedin U.S. Patent No. 5,155,082 which is incorporated herein by reference.Chromium (III) oxides such as crystalline chromium oxide or amorphouschromium oxide are preferred with amorphous chromium oxide being mostpreferred. Chromium oxide (Cr₂O₃) is a commercially available materialwhich may be purchased in a variety of particle sizes. Fluorinationcatalysts having a purity of at least 98% are preferred. Thefluorination catalyst is present in an excess but in at least an amountsufficient to drive the reaction.

The reactor is preheated to the fluorination reaction temperature whileanhydrous HF is fed to the reactor. The stream containing thechlorocarbon feed material, for example the 1,1,2,3-tetrachloropropene,and a stabilizer is introduced into the reaction vessel next, which ismaintained at the desired temperature. The 1,1,2,3,-tetrachloropropene(HCC-1230xf) and HF may be fed to the reactor at any convenienttemperature and pressure. In a preferred embodiment either or both ofthe HCC-1230xf and the HF are pre-vaporized or preheated to atemperature of from about 30° C. to about 300° C. prior to entering thereactor. In another embodiment, the HCC-1230xf and HF are vaporized inthe reactor. The HF and HCC-1230xf feeds are then adjusted to thedesired mole ratio. The HF to HCC-1230xf mole ratio preferably rangesfrom about 3:1 to about 100:1; more preferably from about 4:1 to about50:1 and most preferably from about 5:1 to about 20:1.

The vapor phase fluorination reaction is conducted at a preferredtemperature ranging from about 80° C. to about 400° C.; more preferablyfrom about 100° C. to about 350° C. and most preferably from about 200°C. to about 330° C. Reactor pressure is not critical and can besuperatmospheric, atmospheric or under vacuum. The vacuum pressure canbe from about 5 torr (0.0966 psig) to about 760 torr (14.69 psig).During the vapor phase fluorination reaction, HCC-1230xf and HF arereacted in a vapor phase in the presence of the fluorination catalyst.The reactant vapor is allowed to contact the fluorination catalyst forfrom about 1 to 120 seconds or more preferably from about 1 to 20seconds. For purposes of this invention, “contact time” is the timerequired for the gaseous reactants to pass through the catalyst bedassuming that the catalyst bed is 100% void.

In the preferred embodiment, the process flow is in the down directionthrough a bed of the catalyst. Before each use, the catalyst ispreferably dried, pre-treated and activated. It may also be advantageousto periodically regenerate the catalyst after prolonged use while inplace in the reactor. Pre-treatment can be done by heating the catalystto about 250° C. to about 430° C. in a stream of nitrogen or other inertgas. The catalyst may then be activated by treating it with a stream ofHF diluted with a large excess of nitrogen gas in order to obtain highcatalyst activity. Regeneration of the catalyst may be accomplished byany means known in the art such as, for example, by passing air or airdiluted with nitrogen over the catalyst at temperatures of from about100° C. to about 400° C., preferably from about 200° C. to about 375°C., for from about 8 hours to about 3 days, depending on the size of thereactor.

Thus, it is contemplated that the present reaction may be performedusing a wide variety of process parameters and process conditions inview of the overall teachings contained herein. However, it is preferredin certain embodiments that this reaction step comprises a gas phasereaction, preferably in the presence of catalyst and a stabilizer.

The present reaction also incorporates the use of at least onestabilizer. Applicants have discovered that the addition of at least onestabilizer to the reaction results in significantly increasing thelongevity of the catalyst, preferably by at least 43%, more preferablyby at least 50%. By way of non-limiting explanation, it is believed thatthe presence of the stabilizer substantially prevents the undesirablepolymerization of the starting materials with the catalyst. In theabsence of the stabilizer, the catalyst becomes ineffective after aperiod of several hours due to this polymerizing side-reaction.

Stabilizers suitable for use in the present reaction include those knownfor use in halogenation reactions, and in particular halogenationreactions involving alkanes, alkenes, and alkynes. In some embodiments,the stabilizer is selected from the group comprisingp-tap(4-tert-Amylphenol), methoxy-hydroquinone, 4-methoxyphenol(HQMME),triethylamine, di-isopropyl amine, butylated hydroxy anisole (BHA),thymol and combinations thereof. In certain preferred embodiments, thestabilizer comprises an amine-based stabilizer. More preferably, thestabilizer comprises triethylamine, di-isopropyl amine or combinationsthereof. Of course, combinations of two or more of any of thesestabilizers, or other stabilizers not named here, may be used.

The stabilizer is preferably present in an amount less than 300 ppm,more preferably in an amount less than 100 ppm, and most preferably, inan amount less than 10 ppm. By way of non-limiting explanation, it isbelieved that minimization of stabilizer amounts reduces the potentialdeactivation of the catalyst.

In certain preferred embodiments, the present step of fluorinating atetrachloropropene to produce a C3 haloolefin comprises contacting thetetrachloropropene with a fluorinating agent, preferably underconditions effective to provide a tetrachloropropene conversion of atleast about 50%, more preferably at least about 55%, and even morepreferably at least about 70%. In certain preferred embodiments theconversion is at least about 90%, and more preferably about 100%.Furthermore, in certain preferred embodiments, the present step offluorinating a tetrachloropropene to produce a C3 haloolefin isconducted under conditions effective to provide a C3 haloolefinselectivity of at least about 5%, more preferably at least about 20%,more preferably at least about 50%, and even more preferably at leastabout 90%. In embodiments in which the compound of tetrachloropropenecomprises CH₂ClCCl=CCl₂, and CCl₃CHCl=CH₂ the selectivity to HFO-1233xfis at least about 5%, more preferably at least about 20%, morepreferably at least about 50%, and even more preferably at least about99%.

EXAMPLES

Additional features of the present invention are provided in thefollowing examples, which should not be construed as limiting the claimsin any way.

Examples 1-2

These examples illustrate addition of hydrogen fluoride to CH₂ClCCl=CCl₂in a gas phase reaction in the absence of a stabilizer, which isillustrated by the following reaction scheme:

CH₂ClCCl=CCl₂+3HF→CF₃CCl=CH₂+3HCl

A dual zone reactor was charged with 65 cc of pretreated Cr₂O₃ catalystin the high temperature zone and 65 cc of 4 to 6 wt % FeCl₃/C catalystin the low temperature zone. The reactor was mounted inside a heaterwith two zones. The high temperature zone was maintained at 350° C. andthe low temperature zone was maintained at 180° C. The organic feed(CH₂ClCCl=CCl₂) and hydrogen fluoride were fed via peristaltic pumpsinto the reactor at a rate of about 22 to about 27 g/hr and about 35 toabout 45 g/hr, respectively, which resulted in a HF/organic mole ratioof about 14:1. The gas stream comprising the organic feed and HF waspassed through the catalyst beds over a period of up to about 19 hoursat a pressure of about 30 psig. The contact time through the Cr₂O₃ bedwas about 6.4 seconds and the contact time through the FeCl₃/C bed wasabout 8.8 seconds.

A GC and a GC/MS were used to analyze reactor effluent collected inseparate product collection cylinders at the reactor exit line whichcontained deionized water to absorb the HF and HCl. The organic phase,containing the crude CF₃CCl=CH₂ (HFC-1233xf) product, was then isolatedfrom the mixture by phase separation. In Table 1 below, Example 1 wasreactor effluent material collected between 4 and 13 hours of run time.Also in table 1 below, Example 2 was reactor effluent material collectedbetween 14 and 19 hours of run time. The total conversion of the organicfeed was at least about 57% and the selectivity to HFC-1233xf was atleast about 75%. The results are shown in Table I below.

TABLE I Example 1 Example 2 % 1233xf produced 59.9 45.45 % byproductproduced 18.6 11.9 % organic feed converted 78.5 57.35

Other byproducts produced include underfluorinated intermediatesdichlorodifluoropropene (1232 isomer) and trichlorofluoropropene (1231isomer) in addition to 1,2-dichloro-3,3,3-trifluoropropene (1223xd).

In Examples 1-2, the catalyst was observed to lose substantial activityat about 4 to 5 hours. Upon examination, the catalyst appeared to havefused together in the reactor such that it had to be removed viadrilling. Applicants hypothesize that the observed catalyst fusion maybe due to polymerization of the catalyst with the organic feed.

Example 3-5

These examples illustrate addition of hydrogen fluoride to CH₂ClCCl=CCl₂in a gas phase reaction in the presence of a stabilizer.

The procedure of Examples 1-2 is repeated except that the pressure wasmaintained at about 20 psig, the HF/organic mole ratio was about 16:1,and 20 ppm of HQMME was added to the organic feed as a stabilizer. ForExample 5, the reaction was run until catalyst deactivation, namelyabout 43 hours. The results are shown in Table 2 below.

TABLE II Example 3 Example 4 Example 5 % 1233xf produced 87.4 93.6 95.94% byproduct ≈12.5 ≈6 ≈4 produced % organic feed 99.95 99.99 99.985converted

Other byproducts produced included underfluorinated intermediatesdichlorodifluoropropene (1232 isomer) and trichlorofluoropropene (1231isomer) as well as 1,2-dichloro-3,3,3-trifluoropropene (1223xd) andtetrafluoro-monochloropropane (such as HCFC-244bb).

In comparison with Examples 1-2 where no stabilizer was present,Examples 3-5 demonstrated significantly increased catalyst longevity. Inparticular, the catalyst was substantially functional even after over 40hours of continuous use. In addition, the percent of organic feedconverted increased from approximately 57% conversion to approximately99% conversion with the addition of the stabilizer. In addition, whenthe catalyst was discharged from the reactor its physical appearance hadnot changed unlike the catalyst discharged during Examples 1-2. Thisdemonstrates Applicants' discovery of the unexpectedly superiorperformance of a catalyst in the presently claimed reactions when usedin conjunction with a stabilizer.

Examples 6-20

These Examples illustrate the stability testing of CH₂ClCCl=CCl₂ atdifferent temperatures using different stabilizers in the presence ofcarbon steel, stainless steel and monel metal coupons. Each stabilizerwas used in a concentration of 100 ppm and heated from room temperatureto 100° C. and/or 150° C. Each stabilizer was then ranked according tothe results, with the most poorly stable combinations receiving a ratingof 1 and the most stable combinations at 150° C. receiving a rating of10. The results are shown in Table III below.

TABLE III Stabilizer Carbon steel Stainless Steel Monel Thymol 5 7 8Di-isopropyl Amine 7 10 9 Triethylamine 7 8 10 4-tert-amyl-phenol 1 9 5BHA 1 6 5

Example 21

This Example illustrates the addition of hydrogen fluoride toCH₂ClCCl=CCl₂ in a gas phase reaction using di-isopropyl amine as astabilizer with a relatively long catalyst contact time of about 2seconds. A 1″ monel pipe reactor was charged with 320 cc of fresh Cr₂O₃catalyst at atmospheric pressure and at a temperature of 300° C. Theorganic feed (CH₂ClCCl=CCl₂) and hydrogen fluoride were fed viaperistaltic pumps into the reactor at a rate of about 0.24 lb/hr andabout 0.55 lb/hr, respectively, which results in a HF/organic mole ratioof about 20:1. The di-isopropyl amine stabilizer was added to theCH₂ClCCl=CCl₂ feed in an amount of 10 ppm. The gas stream comprising theorganic feed, HF and stabilizer was passed through the catalyst bed overa period of up to about 85 hours. The contact time through the Cr₂O₃ bedwas about 2.05 seconds.

Reactor effluent was analyzed as in Examples 1-2. After 85 hours ofcontinuous run time, the total conversion of the organic feed was 100%and the selectivity to HFC-1233xf is at least about 90%. The catalystshowed no sign of deactivation or polymerization.

Example 22

This Example illustrates the addition of hydrogen fluoride toCH₂ClCCl=CCl₂ in a gas phase reaction using di-isopropyl amine as astabilizer with a relatively long catalyst contact time of about 8 toabout 10 seconds. A 2″ monel pipe reactor was charged with 1800 cc offresh Cr₂O₃ catalyst at atmospheric pressure and at a temperaturestarting at 200° C. and raised to 225° C. and then 250° C. The organicfeed (CH₂ClCCl=CCl₂) and hydrogen fluoride were fed via peristalticpumps into the reactor at a rate of about 0.35 lb/hr and about 0.78lb/hr, respectively, which resulted in a HF/organic mole ratio of about20:1. The di-isopropyl amine stabilizer was added to the CH₂ClCCl=CCl₂in an amount of 10 ppm. The gas stream comprising the organic feed, HFand stabilizer was passed through the catalyst bed over a period of upto about 278 hours. The contact time through the Cr₂O₃ bed was about 8to about 10 seconds.

Reactor effluent was analyzed as in Examples 1-2. After 278 hours ofcontinuous run time, the total conversion of the organic feed was 100%and the selectivity to HFC-1233xf was at least about 80% to at leastabout 90%. The catalyst showed only minimal signs of deactivation over278 hours of continuous run time, even with prolonged catalyst contacttimes.

Example 23

This example demonstrates the stability of a Cr₂O₃ catalyst during thefollowing reaction:

1,1,2,3-tetrachloropropene (TCP)+HF→1233xf+3HCl

using 3 different TCP feeds. Run A used unstabilized TCP, while Run Bused TCP stabilized with 13 ppm of p-tap, and Run C used TCP stabilizedwith 13 ppm of methoxy-hydroquinone. All three runs used a 1″ reactorwhich was charged with 310 cc (about 448 grams) of freshly pretreatedCr₂O₃ catalyst. The catalyst bed hot spot reaction temperature for allthe runs was kept in a range of 243-254° C. throughout the length of theexperiment. Also, the same flow rates of HF and TCP were used for allthe runs keeping the initial catalyst productivity and contact time thesame for all 3 runs. All runs were performed at atmospheric pressure.

The average flow rate of HF for the experiments were 0.73 lb/hr and theaverage TCP flow rate was 0.43 lb/hr. The mole ratio of HF:TCP was about15.3:1. The contact time for the experiments was about 1.5 seconds andthe initial catalyst productivity (before catalyst deactivation) wasabout 25 lb/hr/ft³ catalyst. Results of the experiments are summarizedin Table IV below. The use of stabilizer allowed the reaction to run aminimum of 43.3% longer than using unstabilized TCP.

TABLE IV Catalyst Activity TCP feed** On-stream time (hrs)* %improvement A 44.5 n/a B 63.75 43.3% C 66.75 50.0% *On-stream time wasdefined as the total amount of time the reaction was run until theconversion of TCP dropped below 75%. **A = unstabilized TCP B = TCPstabilized with 13 ppm p-tap C = TCP stabilized with 13 ppmmethoxy-hydroquinone

Having thus described a few particular embodiments of the invention,various alterations, modifications, and improvements will readily occurto those skilled in the art. Such alterations, modifications, andimprovements, as are made obvious by this disclosure, are intended to bepart of this description though not expressly stated herein, and areintended to be within the spirit and scope of the invention.Accordingly, the foregoing description is by way of example only, andnot limiting. The invention is limited only as defined in the followingclaims and equivalents thereto.

1. A method of preparing fluorinated organic compounds comprisingcontacting at least one chlorocarbon selected from the group consistingof tetrachloropropene and pentachloropropane with a halogenating agentin the presence of at least one catalyst and at least one stabilizerunder conditions effective to produce a C3 haloolefin.
 2. The method ofclaim 1 wherein said C3 haloolefin is 2-chloro-3,3,3,-trifluoropropene.3. The method of claim 2 wherein said chlorocarbon is at least onecompound selected from the group consisting of1,1,2,3-tetrachloropropene, 2,3,3,3-tetrachloropropene,1,1,1,2,3-pentachloropropane.
 4. The method of claim 1 wherein saidhalogenating agent is a fluorinating agent.
 5. The method of claim 4wherein said fluorinating agent comprises hydrogen fluoride.
 6. Themethod of claim 1 wherein at least a portion of said contacting step isconducted at a temperature of from about 80° C. to about 400° C.
 7. Themethod of claim 1 wherein at least a portion of said contacting step isconducted at a pressure of from about 5 torr to about 150 psig.
 8. Themethod of claim 1 wherein said contacting step comprises conducting atleast a portion of said contacting step in the gas phase.
 9. The methodof claim 1 wherein said catalyst comprises at least one fluorinationcatalyst.
 10. The method of claim 9 where the at least one fluorinationcatalyst is selected from the group consisting of Cr₂O₃, FeCl₃/C, Cr₂O₃,Cr₂O₃/Al₂O₃, Cr₂O₃/AlF₃, Cr₂O₃/carbon, CoCl₂/Cr₂O₃/Al₂O₃,NiCl₂/Cr₂O₃/Al₂O₃, CoCl₂/AlF₃, NiCl₂/AlF₃ and combinations thereof. 11.The method of claim 9 wherein at least one fluorination catalystcomprises Cr₂O₃.
 12. The method of claim 1 wherein said stabilizercomprises an amine stabilizer.
 13. The method of claim 1 wherein saidstabilizer comprises a hydroquinone stabilizer.
 14. The method of claim1 wherein said stabilizer is selected from the group consisting ofp-tap(4-tert-Amylphenol), methoxy-hydroquinone, 4-methoxyphenol(HQMME),triethylamine, di-isopropyl amine, butylated hydroxy anisole (BHA),thymol and combinations thereof.
 15. The method of claim 12 wherein saidstabilizer comprises triethylamine.
 16. The method of claim 12 whereinsaid stabilizer comprises di-isopropyl amine.
 17. The method of claim 13wherein said stabilizer comprises methoxy-hydroquinone.
 18. The methodof claim 13 wherein said stabilizer comprises 4-methoxyphenol (HQMME).19. The method of claim 14 wherein said stabilizer comprises p-tap. 20.The method of claim 1 wherein the concentration of said stabilizer isless than about 300 ppm.
 21. The method of claim 20 wherein theconcentration of said stabilizer is less than about 100 ppm.
 22. Themethod of claim 21 wherein the concentration of said stabilizer is about10 ppm or less.
 23. The method of claim 1 wherein said catalyst in thepresence of said stabilizer is substantially operable for a greaterperiod of time than said catalyst wherein said stabilizer is notpresent.
 24. The method of claim 23 wherein said catalyst in thepresence of said stabilizer is substantially operable at least about 40%longer than said catalyst wherein said stabilizer is not present. 25.The method of claim 23 wherein said catalyst in the presence of saidstabilizer is substantially operable at least about 50% longer than saidcatalyst wherein said stabilizer is not present.
 26. The method of claim3 wherein said chlorocarbon is 1,1,2,3-tetrachloropropene.
 27. Themethod of claim 3 wherein said chlorocarbon is2,3,3,3-tetrachloropropene.
 28. The method of claim 3 wherein saidchlorocarbon is 1,1,1,2,3-pentachloropropane.